FSUSB31K8X USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB31K8X is a USB Switch IC manufactured by onsemi, designed for high-speed USB 2.0 applications requiring single-channel DPST (Double Pole Single Throw) switching functionality. This component operates at supply voltages between 3V and 4.3V with a maximum on-state resistance of 10Ω and supports bandwidth up to 720MHz with Break-Before-Make switching characteristics.

The FSUSB31K8X is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production requirements for applications utilizing this interface component.

Substiute Parts

FSUSB31K8X

onsemiIn Stock: 4575FSUSB31K8X Datasheet

Current PartRFQ

FSUSB46K8X

Fairchild SemiconductorIn Stock: 1306FSUSB46K8X Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FSUSB31K8X is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

• Multiplexer/Demultiplexer Circuit: 2:1
• Switch Circuit: DPST
• Number of Channels: 1
• Voltage - Supply, Single (V+): 3V ~ 4.3V
• -3dB Bandwidth: 720MHz
• Features: Break-Before-Make, USB 2.0
• Operating Temperature: -40°C ~ 85°C (TA)
• Mounting Type: Surface Mount
• Package / Case: 8-VFSOP (0.091", 2.30mm Width)

Acceptable Parameter Variations:

• On-State Resistance (Max): Equal to or lower than 10Ω
• RoHS Status: ROHS3 Compliant or equivalent
• Moisture Sensitivity Level (MSL): 1 (Unlimited)
• REACH Status: REACH Unaffected

The FSUSB46K8X meets all mandatory matching parameters and acceptable variation criteria, qualifying it as a direct substitute for the FSUSB31K8X.

Parameter Comparison

Engineering Selection Recommendations

The FSUSB46K8X is suitable as a substitute for the FSUSB31K8X based on the following factors:

Product Status Alignment: The FSUSB46K8X maintains active product status, ensuring continued availability and supply chain support compared to the obsolete FSUSB31K8X.

Compliance Equivalence: Both components maintain ROHS3 compliance and REACH Unaffected status, satisfying regulatory requirements for equivalent applications.

Electrical Performance: The FSUSB46K8X provides improved on-state resistance performance (6.5Ω versus 10Ω maximum), delivering superior electrical characteristics while maintaining identical supply voltage ranges, bandwidth specifications, and switching functionality.

Physical Compatibility: Identical package specifications (8-VFSOP, 0.091", 2.30mm Width) and mounting type (Surface Mount) ensure direct PCB-level compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the FSUSB46K8X directly replace the FSUSB31K8X in existing designs?

A: Yes. Both components share identical package specifications, supply voltage ranges, bandwidth ratings, switching topology (DPST, 2:1 multiplexer), and operating temperature ranges. The FSUSB46K8X provides equivalent or superior electrical performance.

Q: What is the significance of the lower on-state resistance in the FSUSB46K8X?

A: The FSUSB46K8X specifies a maximum on-state resistance of 6.5Ω compared to 10Ω for the FSUSB31K8X. This represents improved electrical efficiency and reduced power dissipation during switching operations, providing a performance advantage in the substitute component.

Q: Are there any compliance or certification differences between these parts?

A: No. Both components maintain identical RoHS3 compliance status, REACH Unaffected designation, and Moisture Sensitivity Level (MSL) rating of 1 (Unlimited).

Q: Why is the FSUSB31K8X classified as obsolete?

A: The FSUSB31K8X is listed as obsolete by the manufacturer. The FSUSB46K8X maintains active product status, making it the recommended choice for new designs and ongoing production support.

Q: Are there any package or pinout considerations for substitution?

A: No. Both components utilize the 8-VFSOP package with identical physical dimensions (0.091", 2.30mm Width) and surface mount mounting type. No PCB layout modifications are required for substitution.